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Exdet
Asked:2024-01-25 20:11:37 +0000 UTC2024-01-25 20:11:37 +0000 UTC

从请求中提取“数据”值的中间件（rust）

  • 772

我应该以 { "data":{ ... } } 的形式接收对 api 的请求。我经常需要从数据中获取所有必要的信息。在请求主体沿着路线进一步前进之前，我怎样才能做到这一点？

#[derive(Debug, Deserialize)]
pub struct ApiData<T> {
    pub data: T,
}

struct ExtractData;

#[rocket::async_trait]
impl<T> Fairing for ExtractData
    where
        T: FromRequest<'static>,
{
    fn info(&self) -> Info {
        Info {
            name: "ExtractData",
            kind: Kind::Request,
        }
    }

    async fn on_request<'a>(&self, req: &'a mut Request<'_>, _: &'a Data<'_>) {
        if let Some(data) = req.guard::<ApiData<T>>().succeeded() {
            req.local_cache(|| data.data);
        } else {
            req.set_abort(Some(Status::BadRequest));
        }
    }
}

#[launch]
async fn rocket() -> _ {
    let db = MongoRepo::init().await;
    rocket::build().manage(db)
        .attach(ExtractData)
        .mount("/api/", routes![get_files_in_directories])
        .mount("/api/usepi/patterns", routes![create_pattern])
        .mount(
            "/api/usepi/patterns/icons",
            FileServer::from(Path::new("./src/icons")),
        )
}

我正在尝试以这种方式实现它，但总是存在类型错误

error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
  --> src/main.rs:54:6
   |
54 | impl<T> Fairing for ExtractData
   |      ^ unconstrained type parameter

我不知道该怎么做，请告诉我

rust

1 个回答

  1. Best Answer
    async fn on_request(&self, req: &mut Request<'_>, data: &mut Data<'_>) {
        if let Some(content_length_str) = req.headers().get_one("Content-Length") {
            if let Ok(content_length) = content_length_str.parse::<usize>() {
                let peek_data_string = String::from_utf8_lossy(data.peek(content_length).await).to_string();
                match serde_json::from_str::<ApiData>(&peek_data_string) {
                    Ok(api_data) => {println!("Deserialized data: {:?}", api_data);}
                    Err(err) => {eprintln!("Error parsing JSON: {:?}", err); }
                }
            } else { eprintln!("Failed to parse Content-Length as usize"); }
        } else { eprintln!("Content-Length header not found"); }
    }
    • 0

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